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authorAndy Lutomirski <luto@kernel.org>2019-07-15 10:08:48 -0700
committerIngo Molnar <mingo@kernel.org>2019-11-26 22:00:12 +0100
commit8e05f1b4f27d07a0f93e7c6fd28525a5d082b85c (patch)
tree0bcf277c56d26e3f4b2f0d033847892fdd1496d3 /arch/x86/kernel/ptrace.c
parent0337b7ebfcb8efb4ea0a9f2b2f284217a1c0e62d (diff)
x86/ptrace: Remove set_segment_reg() implementations for current
seg_segment_reg() should be unreachable with task == current. Rather than confusingly trying to make it work, just explicitly disable this case. (regset->get is used for current in the coredump code, but the ->set interface is only used for ptrace, and you can't ptrace yourself.) Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/ptrace.c')
-rw-r--r--arch/x86/kernel/ptrace.c19
1 files changed, 7 insertions, 12 deletions
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index 066e5b01a7e0..3b3b16932589 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -182,6 +182,9 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
+ if (WARN_ON_ONCE(task == current))
+ return -EIO;
+
/*
* The value argument was already truncated to 16 bits.
*/
@@ -209,10 +212,7 @@ static int set_segment_reg(struct task_struct *task,
break;
case offsetof(struct user_regs_struct, gs):
- if (task == current)
- set_user_gs(task_pt_regs(task), value);
- else
- task_user_gs(task) = value;
+ task_user_gs(task) = value;
}
return 0;
@@ -272,6 +272,9 @@ static u16 get_segment_reg(struct task_struct *task, unsigned long offset)
static int set_segment_reg(struct task_struct *task,
unsigned long offset, u16 value)
{
+ if (WARN_ON_ONCE(task == current))
+ return -EIO;
+
/*
* The value argument was already truncated to 16 bits.
*/
@@ -281,23 +284,15 @@ static int set_segment_reg(struct task_struct *task,
switch (offset) {
case offsetof(struct user_regs_struct,fs):
task->thread.fsindex = value;
- if (task == current)
- loadsegment(fs, task->thread.fsindex);
break;
case offsetof(struct user_regs_struct,gs):
task->thread.gsindex = value;
- if (task == current)
- load_gs_index(task->thread.gsindex);
break;
case offsetof(struct user_regs_struct,ds):
task->thread.ds = value;
- if (task == current)
- loadsegment(ds, task->thread.ds);
break;
case offsetof(struct user_regs_struct,es):
task->thread.es = value;
- if (task == current)
- loadsegment(es, task->thread.es);
break;
/*